Engine cranks up but dies when I release the key to the run position

[Zacharay55]

I recently traded a bass tracker for a 1989 stratos 1700xl which has a OMC cobra 3 litre in it. The guy says it ran great before he winterized it and hadn't touched it this year. He's a buddy so I believe him. I bought a new battery for it and go to crank it, and the solenoid was sticking. After tapping it with a hammer it turned over and was trying to fire up. My problem is , is that it will crank and run while I hold the ignition in start, but when I release the key it dies like it hd no power. I changed the coil and ignition switch. I have no power at the coil, maybe a 1.2 volts but I have over 12 at the ignition switch in the run position. I've pulled the wires from behind the running board and no wires seem to be nicked or chewed on by rodents. The wires all look good. Fuses are good. And accessories and tilt/trin work great. I'm at a loss...

 

[Zacharay55]

Here are some pics of the boat and motor

 

[bruceb58]

Likely your man overboard switch is open. The reason you get 12V to the coil while cranking is because that comes from the starter solenoid.

Jumper that switch and see what happens.

If that still doesn't work, you have an open or high resistance between your coil's resistance wire and your ignition switch. Check your engine connector to see if it has corrosion.

My bet is on the man overboard switch though.

 

[Zacharay55]

I think I have figured the problem out after thinkin and likin at it. On the starter solenoid there's three posts, battery, starter, and run circuits. I'll post a picture, but there is no wire on the run side of solenoid, and two wires on the starter circuits post. If I'm correct, I should be able to test voltage on those two individual wires with key in run position, and the one with voltage should go on the run post and hopefully that will get it. I'll keep you posted.

 

[Benny67]

Bench test the solenoid....I would start there myself

 

[bruceb58]

LOL...the solenoid has NOTHING to do with your problem.

 

[Zacharay55]

So what do you suggest bruceb58? I've checked all the wires. No corrosion. And the man overboard switch wires are feathered together to bypass it. Was like that when I got it..

 

[Benny67]

LOL...the solenoid has NOTHING to do with your problem.

so....what's your solution?

Not sayin' I am right but now that you opened your superior mouth....why don't you solve the mans' problem smarty?

 

[Benny67]

Do you have a wiring diagram for the boat?

 

[bruceb58]

So what do you suggest bruceb58? I've checked all the wires. No corrosion. And the man overboard switch wires are feathered together to bypass it. Was like that when I got it..

You need to start measuring voltages at the ignition switch, man overboard switch and find the wire that leaves the engine connector.

You need to measure with a load.

Unplug your engine connector and measure resistance between the engine connector and the positive post of the coil and see what you find. You should see a couple of ohms for the resistor wire.

And don't bother with the starter solenoid. It's not your issue.

The same wire that feeds the resistance wire of your ignition also goes to the excite terminal of your alternator...just so you know. I thought I had a wiring schematic of your model but the one I have is for one with a electronic ignition so it doesn't help you.

And the man overboard switch wires are feathered together to bypass it. Was like that when I got it..

So what does that exactly mean? Are they twisted together? Soldered together?

 

[Benny67]

Do yourself a favor and get a overall wiring diagram.

 

[Benny67]

Feed 12Vdc directly to the + of the coil and see if it continues to run after you crank it. (disconnect the original wire that is on it)

Put a switch in series with the jumper so you have some sort of way to shut it down if it does continues to run

At least then you will know if it runs that you have it narrowed down to that part of the circuit and hopefully you can just check connections that are directly involved and check continuity till you find the open or dirty connection.

 

[bruceb58]

There should be 2 wires on the positive side of the coil.

 

[Zacharay55]

Bruceb58-- ok, well some info about myself, I'm an aircraft mechanic, I work on planes. Much more intricate and involved than boats. Way more wires. Way more maintenance. And when I get off I hate dealin with electricity. But as I said in my first post, I had checked the ignition switch and changed the coil, and the kill switch was bypassed by tethering the wires together (shade tree ****). Which the kill switch was good to go. The i-switch had voltage with key in run position. Coil however had voltage when I was turnin it over but not in run position. New coil, new i-switch. Neither of which were the problem. I have a wiring diagram. Pulled all the wires previously and checked resistance and continuity, checked all fuses, checked all plugs. Replaced a lot of connectors that were kinda sketchy. New battery, the works. Still was overlookin one thing that you "LOL .. That has nothing to do with it" .. When I got off today I looked at the starter solenoid "that has nothin to do with it" and low and behold, the starter circuit wire and the run circuit wire were both on the same post. So I put the run wire back in its rightful place and I'll be damned. Started and ran like a top. Thanks for yalls help. But Bruce, don't gotta be so cocky about stuff, you underestimated my abilities and knowledge. I didn't think the solenoid had anything to do with it either but it was the missing peice to the puzzle since I had checked everything else and I thought surely the dumbass who put it on had put the solenoid on and wired it correctly. Just hadn't checked cause it was almost under the engine. Thanks again benny67 !

 

[bruceb58]

That means whoever had the boat before wired it up bypassing the resistor wire. Your choice if you leave it that way but you will burn out your coil. Does this engine still have points?

As a test, put your ignition in the run position and rotate the engine so the points are closed. If the voltage at the positive side of the coil reads 12V, you have a miswire.

Out of curiosity, do you have 2 wires on the positive post of the coil? You should.

BTW. Electrical engineer here. Boats are simple stuff I agree.

Good luck.

 

[Zacharay55]

Resistor wire between what and what? And yes the coil has two wire on posotive side. I think the only problem was, was that when they put the solenoid back on , they put the purple wire and the yellow and black wire on the same post. And in my schematic, they go to two different posts.. I think everything is how it is supposed to be now.

 

[bruceb58]

Measure the voltage at the coil with the ignition off and make sure there is no voltage there.

 

[Zacharay55]

Resistor wire between what and what? Yeah I got two wires on posotive post of coil. I think the only problem was, was that whoever had it and put solenoid in , had put the purple wire and yellow and black wire on same post of solenoid. Which one wire goes to one post and one wire goes to the other. Minus the battery post on it. I believe everything is back to factory. Minus the bypassing of the man overboard switch. Which when the switch has the lanyard on it closes the circuit anyways and when it is pulled off the switch it opens the circuit..

 

[bruceb58]

There is a resistor wire between the positive post of your coil and your ignition switch on ignition systems with points. This of course assumes that the PO didn't mess with the wiring which apparently he did.

 

[bruceb58]

If you are going to keep this boat, I suggest getting an OEM service manual. Here is one:

http://www.ebay.com/itm/1989-OMC-CO...759-/121675484164?hash=item1c546c8c04&vxp=mtr

I am sure Benny is familiar with Cobras like I am. I owned one for 12 years so I know a lot about it.